Apparatus, system and method for providing an end effector

ABSTRACT

The disclosure provides an apparatus, system and method for providing an end effector. The end effector may be capable of accommodating semiconductor wafers of varying sizes, and may include: a wafer support; a bearing arm capable of interfacing with at least one robotic element, and at least partially bearing the wafer support at one end thereof; a plurality of support pads on the wafer support for physically interfacing with a one of the semiconductor wafers; and a low friction moving clamp driven bi-directionally along a plane at least partially provided by the bearing arm, wherein the low friction moving clamp retractably applies force to a proximal edge of the semiconductor wafer.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. Non-ProvisionalApplication No. 17/374,846, filed Jul. 13, 2021, entitled: APPARATUS,SYSTEM AND METHOD FOR PROVIDING AN END EFFECTOR, which is a Continuationof U.S. Non-Provisional Application No. 16/806,373, filed Mar. 2, 2020,entitled APPARATUS, SYSTEM AND METHOD FOR PROVIDING AN END EFFECTOR,which is a continuation of U.S. Non-Provisional Application No.15/889,410, filed Feb. 6, 2018, entitled APPARATUS, SYSTEM AND METHODFOR PROVIDING AN END EFFECTOR, which is a continuation of U.S.Non-Provisional Application No. 15/370,125, filed Dec. 6, 2016, entitledAPPARATUS, SYSTEM AND METHOD FOR PROVIDING AN END EFFECTOR.

FIELD OF THE DISCLOSURE

The present disclosure relates to the transfer of articles, such assemiconductor wafers, and more particularly to an end effector forgripping such wafers and a method for handling and transferring suchwafers using the end effector.

DESCRIPTION OF THE BACKGROUND

The use of robotics is well established as a manufacturing expedient,particularly in applications where human handling is inefficient and/orundesirable. One such circumstance is in the semiconductor arts, inwhich robotics are used to handle wafers during various process steps.Such process steps may include, by way of example, chemical mechanicalplanarization (CMP), etching, deposition, passivation, and various otherprocesses in which a sealed and/or “clean” environment must bemaintained, such as to limit the likelihood of contamination and toensure that various specific processing conditions are met.

Current practice in the semiconductor arts to robotically handle thesewafers often includes the use of an end effector operably attached tothe robotics, such as in order to load semiconductor wafers from aloading stack into the various processing ports that may correspond tothe aforementioned exemplary process steps. The robotics are employed todeploy the end effector to retrieve the wafer from a particular port orstack, such as before and/or after processing in an associated processchamber. The wafer may thus be shuttled by the robotics connectivelyassociated with the end effector to subsequent ports for additionalprocessing. When the wafer processing stages are complete, the roboticsmay then return the processed semiconductor wafer to a loading port, andmay, again using the end effector, then retrieve the next wafer forprocessing by the system. It is typical that a stack of severalsemiconductor wafers is processed in this manner using the end effectorduring each process run.

Typical end effectors hold the wafer on its bottom side, such as usingbackside suction provided by, for example, vacuum draw eyelets on theend effector. The application of other mechanical forces directly to thewafer is atypical, in part because the application of mechanical forcesis generally understood to have a high likelihood of damaging orcontaminating the wafer.

Accordingly, there is a need for an end effector that may readily handleand transfer very thin semiconductor wafers, preferably of multiplewafer sizes and for multiple process steps, without damaging orcontaminating such wafers.

SUMMARY

Certain embodiments are and include an apparatus, system and method forproviding an end effector. The end effector may be capable ofaccommodating semiconductor wafers of varying sizes, and may include: awafer support; a bearing arm capable of interfacing with at least onerobotic element, and at least partially bearing the wafer support at oneend thereof; a plurality of support pads on the wafer support forphysically interfacing with a one of the semiconductor wafers; and a lowfriction moving clamp driven bi-directionally along a plane at leastpartially provided by the bearing arm, wherein the low friction movingclamp retractably applies force to a proximal edge of the semiconductorwafer to provide the physical interfacing of the semiconductor waferwith the plurality of support pads.

The wafer support may be or include a fork portion. The wafer supportmay also include presence sensing for wafers. The varying sizes ofwafers held by the wafer support may include, by way of non-limitingexample, 200 mm and 300 mm wafers.

The bi-directional drive may include at least a moving clamp motor. Alow friction vacuum cylinder may be engaged for the moving clamp motor.The vacuum cylinder may consist of a seal-less glass tube with agraphite piston.

The end effector may also include at least one retract stop that stopsretraction of the low friction moving clamp after actuation of the lowfriction moving clamp by the bi-directional drive. The at least oneretract stop may be vacuum operated. The at least one retract stop maybe, for example, a popping “button” stop.

The low friction moving clamp may include an angular strike face toapply the strike force to the wafer. The angular strike face may pivotabout a substantially center pivot point in order to optimally engagethe wafer. The low friction moving clamp further may include two cantedrollers at the outermost portions thereof which are capable ofsubstantially imparting the strike force to the wafer edge.

The plurality of support pads may include at least four support pads,wherein at least two of the four support pads are proximal to thebearing arm, and wherein at least two others of the support pads aredistal to the bearing arm. The at least two distal support pads each mayeach include a ramped portion and a roller portion having a center axiscanted in relation to a center axis of the semiconductor wafer. The atleast two proximal support pads may also include a ramped portion. Theproximal support pads and/or the distal support pads may additionallyinclude a raised ridge portion.

Thus, the disclosure provides at least an apparatus, system and methodfor providing an end effector that may readily handle and transfer verythin semiconductor wafers of multiple wafer sizes and for multipleprocess steps, without damaging or contaminating such wafers

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplary compositions, systems, and methods shall be describedhereinafter with reference to the attached drawings, which are given asnon-limiting examples only, in which:

FIG. 1 is an illustration of a wafer handling system according to thedisclosed embodiments;

FIG. 2 is an illustration of an end effector according to the disclosedembodiments;

FIG. 3 is an illustration of an end effector according to the disclosedembodiments;

FIG. 4 is an illustration of an end effector according to the disclosedembodiments;

FIG. 5 is an illustration of wafer support pads according to thedisclosed embodiments;

FIG. 6 is an illustration of wafer support pads according to thedisclosed embodiments;

FIG. 7 is an illustration of an end effector according to the disclosedembodiments;

FIG. 8 is an illustration of a moving clamp according to the disclosedembodiments;

FIG. 9 is an illustration of a wafer support pad according to thedisclosed embodiments;

FIG. 10 is an illustration of an end effector according to the disclosedembodiments;

FIG. 11 is an illustration of an end effector according to the disclosedembodiments;

FIG. 12 is an illustration of a wafer support pad according to thedisclosed embodiments;

FIG. 13 is an illustration of a moving clamp motor according to thedisclosed embodiments;

FIG. 14 is an illustration of a moving clamp motor according to thedisclosed embodiments;

FIG. 15 is an illustration of a moving clamp motor according to thedisclosed embodiments; and

FIG. 16 is an illustration of a processing system according to thedisclosed embodiments.

DETAILED DESCRIPTION

The figures and descriptions provided herein may have been simplified toillustrate aspects that are relevant for a clear understanding of theherein described apparatuses, systems, and methods, while eliminating,for the purpose of clarity, other aspects that may be found in typicalsimilar devices, systems, and methods. Those of ordinary skill may thusrecognize that other elements and/or operations may be desirable and/ornecessary to implement the devices, systems, and methods describedherein. But because such elements and operations are known in the art,and because they do not facilitate a better understanding of the presentdisclosure, for the sake of brevity a discussion of such elements andoperations may not be provided herein. However, the present disclosureis deemed to nevertheless include all such elements, variations, andmodifications to the described aspects that would be known to those ofordinary skill in the art.

Embodiments are provided throughout so that this disclosure issufficiently thorough and fully conveys the scope of the disclosedembodiments to those who are skilled in the art. Numerous specificdetails are set forth, such as examples of specific components, devices,and methods, to provide a thorough understanding of embodiments of thepresent disclosure. Nevertheless, it will be apparent to those skilledin the art that certain specific disclosed details need not be employed,and that embodiments may be embodied in different forms. As such, thedisclosed embodiments should not be construed to limit the scope of thedisclosure. As referenced above, in some embodiments, well-knownprocesses, well-known device structures, and well-known technologies maynot be described in detail.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. For example, asused herein, the singular forms “a”, “an” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The steps, processes, and operations described herein are notto be construed as necessarily requiring their respective performance inthe particular order discussed or illustrated, unless specificallyidentified as a preferred or required order of performance. It is alsoto be understood that additional or alternative steps may be employed,in place of or in conjunction with the disclosed aspects.

When an element or layer is referred to as being “on”, “upon”,“connected to” or “coupled to” another element or layer, it may bedirectly on, upon, connected or coupled to the other element or layer,or intervening elements or layers may be present, unless clearlyindicated otherwise. In contrast, when an element or layer is referredto as being “directly on,” “directly upon”, “directly connected to” or“directly coupled to” another element or layer, there may be nointervening elements or layers present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). Further, as used herein the term “and/or” includes anyand all combinations of one or more of the associated listed items.

Yet further, although the terms first, second, third, etc. may be usedherein to describe various elements, components, regions, layers and/orsections, these elements, components, regions, layers and/or sectionsshould not be limited by these terms. These terms may be only used todistinguish one element, component, region, layer or section fromanother element, component, region, layer or section. Thus, terms suchas “first,” “second,” and other numerical terms when used herein do notimply a sequence or order unless clearly indicated by the context. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the embodiments.

FIG. 1 illustrates an automated wafer handling system 100 suitable toprecisely handle semiconductor wafers or substrates 102, such as siliconwafers, of varying diameters, compositions and physical attributes. Thehandling system 100 may be capable of supplying wafers 102 in a rapid,ordered succession for wafer processing. The wafers 102 supplied may bemanipulated or transferred among various locations for processing, inpart, by robotics, such as a robotic arm 104, equipped with an edge gripend effector 106 adapted to perform the aforementioned manipulation andtransfer.

The robotic arm 104 and end effector 106 cooperate to place and removewafers 102 to and from wafer processes, one or more wafer aligners, andone or more wafer cassettes, by way of non-limiting example. To thatend, the end effector 106 may include one or more vacuum eyelets 108 tosecurely hold a subject wafer 102 in the vertical, horizontal, andinverted orientations required during wafer processing, in addition toproviding or supplementing the various wafer gripping aspects discussedherein throughout.

As such, the example of FIG. 1 illustrates a system 100 in which theexemplary end effectors 106 disclosed herein below may be operable. Inshort, the illustrated edge grip end effector 106, which isrepresentative of the various types of end effectors 106 discussedbelow, may retrieve wafers 102 from one or more cassettes, such as forclocking of the retrieved wafers with a process aligner, and/orsubsequently with various wafer processes. More particularly, thevarious end effector types provided in certain of the embodiments mayprovide for use of a single end effector 106 with multiple differentwafer diameters through the various referenced wafer processes.

Not only do semiconductor wafers vary in diameter, they are alsotypically manufactured according to standardized specifications which,among other dimensional tolerances including the diameter, require thesurface for receiving device builds thereon to be substantially planar,such as with a flatness of 1.5 microns or less. Further and by way ofexample, 200 mm silicon wafers, for example, have a standard diameter of200+/-0.2 mm and a standard thickness such as 675+/-25 microns. Atypical wafer thickness after processing may range from about 500microns to about 700 microns. Additionally, silicon wafers may beprovided with a specific flat or a notch used for alignment and/orindicative of crystalline orientation. Hence, maintenance of waferflatness during interaction of the wafer with the end effector 106 iskey to obtaining acceptable levels of wafer throughput and waste.

Thinner wafers may be particularly useful for certain integrated circuitapplications, especially in those applications that necessitate moreminimal thicknesses after processing. However, wafer processing mayintroduce warpage or bowing that exceeds the allowable flatness, andsome wafers may have warpage or bowing beyond the desirable levels evenin an unprocessed state. Moreover, warpage or bending may cause improperplacement or alignment of the aforementioned alignment flat or notch. Insuch cases, wafer processing may be adversely affected by the warpage orbending, and these adverse effects may be exacerbated by any warpage orbending imparted by end effector 106.

The foregoing issues resultant from warpage and bowing may beexacerbated for thinner wafers. Accounting for flatness beyond varianceis thus a significant issue in modern wafer processing, and the abilityto account for flatness variance is yet more significant and complex inwafer handlers that allow for different wafer sizes for waferprocessing. Thus, the providing of an end effector 106 that minimizesthe impact of interaction by the end effector on wafer flatness, andthat perhaps even provides remediation of wafer warpage, is highlyadvantageous in the disclosed embodiments.

FIG. 2 illustrates an exemplary edge grip end effector 106 according tocertain of the embodiments. In the illustration of FIG. 2 , the endeffector 106 includes a fork portion 202 on which a silicon wafer 102may rest upon retrieval, and a bearing arm 204 that may interface to oneor more robotics, such as the robotic arm illustrated in FIG. 1 . Thefork portion 202 may be comprised of, by way of non-limiting example,17.4 pH stainless steel, heat-treated to H900 condition. Of note, thefork portion 202 discussed throughout is merely exemplary of a wafersupport that may be at least partially supported by bearing arm 204.That is, other types of wafer supports may be used in certain of theembodiments, such as a spatula type or a ring type, by way of example.

The bearing arm 204 may include, for example, electronic circuitry foractuating one or more electromechanical elements within or on thebearing arm 204, such as for causing the physical association of thefork portion 202 with a wafer 102. The bearing arm 204 may additionallyinclude sensors, processing capabilities, computer memory, networkingcapabilities, such as wireless connectivity, unique identifications(such as RF identification), process counters, electromechanicalinteractions with the robotic arm 104, batteries, such as high-densityrechargeable batteries, and the like.

An electromechanical element associated with the bearing arm 204 forcausing a physical interaction between the fork portion 202 and thewafer 102 may be moving clamp 210. The moving clamp may include, such ason the portion thereof that abuts wafer 102, one or more pads forminimizing interaction forces between the moving clamp 210 and the wafer102. The moving clamp 210 may be electromechanically actuated, such asby directly or indirectly, and such as by one or more vacuum, pneumaticor motorized actuators, or may be mechanically actuated, such as viaspring actuation, to extend outwardly from the bearing arm 204 towardthe fork portion 202 in order to grip, move, or otherwise align asilicon wafer 102 for physical association with the fork portion 202.

Further illustrated in FIG. 2 is a plurality of, such as four, pads 212a-d on which the silicon wafer 102 physically associated with the forkportion 202 and subjected to the moving clamp 210 may rest. In theillustration, the support pads 212 a-d may be ramped, such as whereinthe pads 212 a-d are sloped downward toward the center of the siliconwafer 102, or may be ridged, such as to provide support for or stoppageof movement of the wafer 102 when the wafer 102 is physically associatedwith the pad 212 a-d. The support pads 212 a-d may be smooth,semi-frictional, or highly frictional along the surfaces thereof, andmay vary among the foregoing on different surfaces thereof. In theillustrated embodiment, the support pads 212 a-b proximate to the movingclamp 210 physically differ from the pads 212 c-d at the distal end ofthe fork portion 202, at least in that the distal support pads 212 c-dact as clamp pads. That is, for certain pads 212 c-d, a raised/ridgedportion associated with the pad edges most distant from the moving clamp210 may serve to provide pressure against the most distal portion of thecircumference of the wafer 102 associated with the fork portion 202. Asreferenced, this may differ from the simple ramped support pads 212 a-bat the base of the fork portion 202 most proximate to the moving clamp210.

FIG. 3 illustrates an embodiment of an edge grip end effector 106. Inthe illustration, an alternative type of moving clamp 210 may beprovided, and consequently the clamp emergence slot 302 at the base ofthe fork portion 202 is enlarged to allow for emergence and retractionof the alternatively shaped moving clamp 210. Moreover, in the exemplaryillustration of FIG. 3 , the proximate support pads 212 a-b now includea ridge at the distal portion thereof with respect to the center of thewafer, such as to provide a stop for movement of the wafer 102. Yetfurther, the support pads 212 c-d at the most distal aspect of the forkportion 202 from the moving clamp 210 may include the illustrated rollertips 306 to better provide for physical interaction with and stoppage ofmovement of a wafer 102 associated with the fork portion 202 withminimal risk of damage to the wafer.

Roller tips 306 may or may not be canted so as to better grip anassociated wafer 102. Canted roller tips 306 may particularly improvethe handling of worked or thick wafers, and may accordingly be providedproximal to and/or distal from the moving clamp 210. Roller tips 306 maybe, for example, formed of stainless steel, and may improve thecentering of particularly thin wafers physically associated with thefork portion 202.

FIG. 4 illustrates an embodiment of an end effector 106. The example ofFIG. 4 is similar to that of FIG. 3 , but does not include the bearingarm cover 312 on bearing arm 204 of FIG. 3 . In the illustration of FIG.4 , the roller tip support pads 212 c-d and ridged proximal support pads212 a-b are again included on the fork portion 202. Additionallyillustrated in FIG. 4 is a wafer detection system 404, which is shown atthe most distal portion of the fork portion 202 by way of non-limitingexample. Such a wafer detection system 404 may be or include, by way ofnon-limiting example, a fiber-optic beam that detects the presenceand/or characteristics of a wafer 102 physically associated with thefork portion 202.

Also illustrated in FIG. 4 is a moving clamp in the form of an angularmoving clamp 210 that, upon actuation, emerges from the emerging slot302 within the bearing arm housing 312. This angular clamp 210 iselectromechanically actuated, as shown, such as by an actuator 420, andmay be subject to drive length limitations that limit the availablelinear travel distance of the angularly moving clamp 210.

FIG. 5 is an additional illustration of exemplary roller pads 212 c-d atthe distal end of the fork portion 202. In the illustration, it isevident that not only are these exemplary distal support pads 212 c-dprovided with roller portions 306, but further that these exemplarysupport pads 212 c-d are ramped with a downward slope towards the centerof a silicon wafer 102 associated with the fork portion 202.

It will be appreciated that angled or curved support pads may include adual surface area for receiving the wafer, such that the wafer cannothit a corner and thereby not have sufficient surface area to be gripped.This angle or curvature may be smaller on the inside angle and larger onthe outside angle, by way of non-limiting example. Moreover, the rampdesign discussed throughout for the support pads may also improve gripwhile precluding lower wafer features from bottoming on the fork portion202.

Distal support pads 212 c-d with a roller portion 306 may be viewed withparticularity in the illustration of FIG. 6 . FIG. 6 provides across-sectional view of a distal support pad 212 c having ramp androller portions 602, 306, wherein the distal circumference 606 of thesilicon wafer 102 abuts the roller portion 306 of the distal support pad212 c, such as when engaged at the proximal circumference by the movingclamp 210. The engaging angular moving clamp 210 may be, by way ofnon-limiting example only, the moving clamp 210 illustrated in FIG. 4 .

Of particular note with respect to the illustrations of FIGS. 4, 5, and6 , it is optimal that the end effector fork portion 202 avoids contact,to the extent possible, with the bottom of a wafer 102 physicallyassociated therewith. This functionality may be provided by the rampnature of the support pads 212 a-d, such as in conjunction with distalsupport pads 212 c-d having rollers 306 thereon, and may additionallyinclude bends in or ramping features on the fork portion 202. By way ofadditional example, the prongs 630 of the fork portion 202 may bend witha slight slope downward towards a center point between the prongs 630.That is, proximate to the bearing arm the fork portion 202 may beincluded one or more bends, ramps, or upward or downward slopes, and, insuch embodiments, the prongs 630 of the fork portion may or may notinclude a corresponded slope, bend or ramp towards the distal supportpads 212 c-d.

FIG. 7 illustrates an exemplary angular moving clamp 210. In theembodiment of FIG. 7 , the angular clamp 210 includes a first pivotpoint 702 about which the angle Θ of the clamp may pivot in order toimprove centering of the wafer 102 associated with the strike face ofthe moving clamp 210. Moreover, and by way of non-limiting example only,the angular moving clamp 210 of FIG. 7 additionally includes cantedrollers 706 a-b at the outermost portions of the angular moving clamp210. These rollers 706 a-b may or may not be canted in certainembodiments, and may serve to gently press upon an edge of the wafer102, such as by pressing the wafer 102 against a ramped, ridged, and/orroller portion of the support pads 212 a-d.

FIG. 8 illustrates an exemplary angular moving clamp 210. In theembodiment of FIG. 8 , and by way of non-limiting example, pivot point702 for the moving clamp 210 may be provided substantially at the centerpoint of the clamp angle Θ. Further provided are secondary pivot points802 a-b for receiving one or more rollers 706 a-b at substantially theoutermost portions from pivot point 702 of the angular moving clamp 210.Such rollers 706 a-b may or may not be received at pivots 802 a-b incanted manner similar to the exemplary canted roller illustrated in FIG.7 .

FIG. 9 provides an exemplary illustration of a support pad 902, such asmay be used as a proximal or distal support pad or pads 212 a-d. In theexample of FIG. 9 , the support pad 902 is provided with a ridge 904 atthe topmost portion of a ramp 906, and the ridge 904 provided may havetwo distinct planar portions, such as an angular or curved portion 910,on the upper surface thereof. Moreover, and by way of non-limitingexample, the ramped portion 906 of the support pad 902 of FIG. 9 mayadditionally include one or more ridges or distinct planes 912. Theupper ridge, such as may include an angular or curved portion, mayprovide improved positioning of a wafer 102 associated with the forkportion 202 in certain embodiments. A ridged ramp 902 may improvecontact with and centering of a wafer 102 associated with the forkportion 202.

FIG. 10 illustrates an embodiment in which a rectangular moving clamp210, such as the exemplary embodiment illustrated with respect to FIG. 2, moves along a slot 1002 along the bearing arm 204 toward the forkportion 202 as shown, may allow for two or more different types ofwafers 102 a, 102 b to be physically associated with the fork portion202. More specifically and by way of non-limiting example, in theembodiment of FIG. 10 the moving clamp 210 is shown as beingpositionally available to accommodate a 200 mm or a 300 mm wafer inphysical association with the fork portion 202. Moreover, illustrated atthe most distal portion of the fork portion 202 in FIG. 10 are distalsupport pads 902a-b such as those shown in FIG. 9 , which are used toimprove wafer contact for wafers having radii of differing geometries.Of course, other types of support pads 212 a-d referenced throughout maybe used in the embodiment of FIG. 10 , and/or with other embodimentsdiscussed herein throughout.

FIG. 11 illustrates an embodiment similar to that of FIG. 10 in which,rather than a rectangular moving clamp 210, an angular moving clamp 210is employed. The angular clamp 210 of FIG. 11 is provided with rollertips 706 a-b at the most distal angular portions of the angular clamp210. Moreover, in this particular illustration, the distal support pads212 c-d also include roller tips 306.

FIG. 12 illustrates an embodiment of a roller tip distal support pad 212c. The illustrated distal roller support pad 212 c may be provided foruse in certain of the embodiments discussed throughout, such as in theembodiment illustrated in FIG. 11 by way of non-limiting example. In theillustration of FIG. 12 , the rollers 1140 are canted, with a tiltinwards towards the center of a wafer 102 associated with the forkportion 202. Such roller tips 1140 may, for example, particularlyprevent edge friction on thin, knife-edged wafers, such as wafers havingan edge thickness of 50 - 150 um. Also cross-sectionally illustrated inFIG. 12 is an adjustment 1144 for the roller cant, as well as a mappingfeature 1146 that may be associated with the roller tip 1140 for mappinga wafer 102 associated with the fork portion 202.

FIG. 13 illustrates an exemplary clamp motor 1210, which resides on thebearing arm 204 and which actuates a moving clamp 210 to move the clampoutwardly toward the distal end of the fork portion 202 for engagingwith a wafer 102, as discussed herein throughout. In the illustration ofFIG. 13 , a rectangular moving clamp 210 is illustrated, although itwill be appreciated in light of the discussion herein that an angularmoving clamp 210 might instead be provided with the embodiment of FIG.13 .

Illustrated by way of non-limiting example is a low-friction actuator1212, such as a vacuum cylinder, for engaging the moving clamp 210. Thislow-friction vacuum cylinder 1212 may enable low clamping forces so asto prevent or minimize damage to the wafer 102. In general, the movingclamp of certain of the embodiments may be actuated using low frictionmechanisms. By way of example, low friction actuation may be a longstroke actuation, such as a 121 mm stroke by way of non-limitingexample, but may be configurable to any length.

Yet more particularly and by way of non-limiting example, the movingclamp actuator 1212 may be a vacuum cylinder with a glass tube andgraphite piston in a seal-less design (i.e., an air pot). Such anactuator 1212 may allow for very low clamping loads, such as clampingloads of 2oz. or less. Of course, a low-friction roller slide (such asslide 1226 of FIG. 14 ) in conjunction with a low friction moving clampactuator 1212 may further limit prospective damage to the wafer.Nevertheless, it will be appreciated that other actuation methodologies1212, such as electric motors, may also be employed in the embodiments.

The clamp force and clamp speed of moving clamp 210 may be subject toadjustment and control 1222, as is also illustrated in FIG. 13 . Thisadjustment and control 1222 may further minimize damage to a wafer 102associated with the fork portion 202. As such, high-precision control1222 may be provided for the moving clamp stroke, such as a precisionflow control that meters air to vacuum cylinder 1212 in order to controlthe clamping speed.

Position sensing 1220 may also occur with regard to movement of themoving clamp 210 in certain of the embodiments. The position of themoving clamp 210 may be directly or indirectly assessed by positionsensing 1220, such as wherein the position of low-friction roller slide1226 used to slide the moving clamp 210 towards the fork portion 202 isassessed, rather than the actual position of the clamp 210. Of note, anymovement of the moving clamp 210, such as along low friction slide 1226or along any other track, may be low-friction in nature, at leastbecause minimizing friction may also minimize prospective damage to awafer 102 that is associated with the fork portion 202.

FIG. 14 illustrates an additional embodiment of a dual position clampmotor 1210 for use with certain of the embodiments discussed herein.Similarly to FIG. 13 , the certain embodiment of FIG. 14 includes a lowfriction roller slide 1226, one or more low-friction vacuum cylinders1212 for actuating the moving clamp 210, and clamp speed controller 1222to minimize the likelihood of wafer damage.

FIG. 14 also illustrates multiple position sensors 1220 a, b, c forsensing the position of the moving clamp 210. By way of non-limitingexample, first position sensor 1220 a may indicate that the moving clamp210 is fully retracted. Second position moving sensor 1220 b mayindicate that the moving clamp 210 is engaging with a first, largerwafer size, such as a 300 mm wafer 102 a. Third position sensor 1220 cmay indicate that the moving clamp 210 has reached its maximum allowabletravel distance, and is thereby engaging the smallest allowable wafersize for association with the fork portion, such as a 200 mm wafer 102b.

FIG. 14 also illustrates a retractable stop 1240 to limit the retractioncapability of the moving clamp 210 for smaller wafer sizes, such as fora 200 mm wafer 102 b. The retract stop 1240 may also serve as a travelstop, rather than a retraction stop, as will be understood in light ofthe discussion herein. The retract stop 1240 may, by way of non-limitingexample, be vacuum-operated and/or spring extended. Moreover, aplurality of retract or travel stops may be included to support avariety of wafer types having different moving clamp stroke distances,each associated with a respective one of the travel or retract stops.

FIG. 15 is an illustration similar to that of FIG. 14 , but with theretract stop 1240 extended. As illustrated, extension of the retractstop 1240 may shorten the clamp cycle distance, such as to limit theability of the clamp to retract back towards the bearing arm housing 212when smaller wafer sizes, such as a 200 mm wafer, are physicallyassociated with the fork portion 202. This may save cycle time forsmaller wafer sizes. Of additional note, one or more retract stops 1240may be included to save cycle times for different size wafers, asreferenced above.

Therefore, the disclosure provides the ability to handle multiple, suchas dual, wafer sizes without need to change over the end effector. Thiscapability is, in part, provided by an actuated moving clamp. The movingclamp may be vacuum-powered, motorized, pneumatic, spring-actuated, orthe like. Due to the exemplary use of low friction wafer clamping, suchas via a low-friction piston drive and/or a low-friction slideassociated with the moving clamp, precise speed and lower loads are madeavailable through the use of certain of the embodiments, which minimizefriction and thus prospective wafer damage while nevertheless improvingwafer grip.

The foregoing apparatuses, systems and methods may also include thecontrol of the various robotic functionality referenced throughout. Suchcontrol may include, by way of non-limiting example, manual controlusing one or more user interfaces, such as a controller, a keyboard, amouse, a touch screen, or the like, to allow a user to inputinstructions for execution by software code associated with the roboticsand with the systems discussed herein. Additionally, and as is wellknown to those skilled in the art, system control may also be fullyautomated, such as wherein manual user interaction only occurs to “setup” and program the referenced functionality, i.e., a user may onlyinitially program or upload computing code to carry out thepredetermined movements and operational sequences discussed throughout.In either a manual or automated embodiment, or in any combinationthereof, the control may be programmed, for example, to relate the knownpositions of wafers, the bearing arm, the fork portion, and so on.

FIG. 16 illustrates an exemplary embodiment of a computer processingsystem 1400 that may be operably employed in embodiments discussedherein, including to program the robotic control, and that mayaccordingly perform the processing and logic discussed throughout. Thatis, the exemplary computing system 1400 is just one example of a systemthat may be used in accordance with herein described systems andmethods.

Computing system 1400 is capable of executing software, such as anoperating system (OS) and one or more computing applications 1490. Thesoftware may likewise be suitable for operating and/or monitoringhardware, such as via inputs/outputs (I/O), using said applications1490.

The operation of exemplary computing system 1400 is controlled primarilyby computer readable instructions, such as instructions stored in acomputer readable storage medium, such as hard disk drive (HDD) 1415,optical disk (not shown) such as a CD or DVD, solid state drive (notshown) such as a USB “thumb drive,” or the like. Such instructions maybe executed within central processing unit (CPU) 1410 to cause computingsystem 1400 to perform the disclosed operations. In many known computerservers, workstations, PLCs, personal computers, mobile devices, and thelike, CPU 1410 is implemented in an integrated circuit called aprocessor.

The various illustrative logics, logical blocks, modules, and engines,described in connection with the embodiments disclosed herein may beimplemented or performed with any of a general purpose CPU, a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a field programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof, respectively acting as CPU 1410.A general-purpose processor may be a microprocessor, but, in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is appreciated that, although exemplary computing system 1400 isshown to comprise a single CPU 1410, such description is merelyillustrative, as computing system 1400_may comprise a plurality of CPUs1410. Additionally, computing system 1400 may exploit the resources ofremote or parallel CPUs (not shown), for example, through local orremote communications network 1470 or some other data communicationsmeans.

In operation, CPU 1410 fetches, decodes, and executes instructions froma computer readable storage medium, such as HDD 1415. Such instructionscan be included in the software, such as the operating system (OS),executable programs/applications, and the like. Information, such ascomputer instructions and other computer readable data, is transferredbetween components of computing system 1400 via the system’s maindata-transfer path. The main data-transfer path may use a system busarchitecture 1405, although other computer architectures (not shown) canbe used, such as architectures using serializers and deserializers andcrossbar switches to communicate data between devices over serialcommunication paths.

System bus 1405 may include data lines for sending data, address linesfor sending addresses, and control lines for sending interrupts and foroperating the system bus. Some busses provide bus arbitration thatregulates access to the bus by extension cards, controllers, and CPU1410. Devices that attach to the busses and arbitrate access to the busare called bus masters. Bus master support also allows multiprocessorconfigurations of the busses to be created by the addition of bus masteradapters containing processors and support chips.

Memory devices coupled to system bus 1405 can include random accessmemory (RAM) 1425 and read only memory (ROM) 1430. Such memories includecircuitry that allows information to be stored and retrieved. ROMs 1430generally contain stored data that cannot be modified. Data stored inRAM 1425 can generally be read or changed by CPU 1410 or othercommunicative hardware devices. Access to RAM 1425 and/or ROM 1430 maybe controlled by memory controller 1420. Memory controller 1420 mayprovide an address translation function that translates virtualaddresses into physical addresses as instructions are executed. Memorycontroller 1420 may also provide a memory protection function thatisolates processes within the system and that isolates system processesfrom user processes. Thus, a program running in user mode can normallyaccess only memory mapped by its own process virtual address space; itcannot access memory within another process’ virtual address spaceunless memory sharing between the processes has been set up.

The steps and/or actions described in connection with the aspectsdisclosed herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two, incommunication with memory controller 1420 in order to gain the requisiteperformance instructions. That is, the described software modules toperform the functions and provide the directions discussed hereinthroughout may reside in RAM memory, flash memory, ROM memory, EPROMmemory, EEPROM memory, registers, a hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Any one ormore of these exemplary storage medium may be coupled to the processor1410, such that the processor can read information from, and writeinformation to, that storage medium. In the alternative, the storagemedium may be integral to the processor. Further, in some aspects, theprocessor and the storage medium may reside in an ASIC. Additionally, insome aspects, the steps and/or actions may reside as one or anycombination or set of instructions on an external machine readablemedium and/or computer readable medium as may be integrated through I/Oport(s) 1485, such as a “flash” drive.

In addition, computing system 1400 may contain peripheral controller1435 responsible for communicating instructions using a peripheral busfrom CPU 1410 to peripherals and other hardware, such as printer 1440,keyboard 1445, and mouse 1460. An example of a peripheral bus is thePeripheral Component Interconnect (PCI) bus.

One or more hardware input/output (I/O) devices 1485 may be incommunication with hardware controller 1490. This hardware communicationand control may be implemented in a variety of ways and may include oneor more computer busses and/or bridges and/or routers. The I/O devicescontrolled may include any type of port-based hardware (and mayadditionally comprise software, firmware, or the like), and can alsoinclude network adapters and/or mass storage devices from which thecomputer system 1400 can send and receive data for the purposesdisclosed herein. The computer system 1400 may thus be in communicationwith the Internet or other networked devices/PLCs via the I/O devices1485 and/or via communications network 1470.

Display 1160, which is controlled by display controller 1155, mayoptionally be used to display visual output generated by computingsystem 1400. Display controller 1155 may also control, or otherwise becommunicative with, the display. Visual output may include text,graphics, animated graphics, and/or video, for example. Display 1160 maybe implemented with a CRT-based video display, an LCD-based display, gasplasma-based display, touch-panel, or the like. Display controller 1155includes electronic components required to generate a video signal thatis sent for display.

Further, computing system 1400 may contain network adapter 1465 whichmay be used to couple computing system 1400 to an external communicationnetwork 1470, which may include or provide access to the Internet, andhence which may provide or include tracking of and access to the processdata discussed herein. Communications network 1470 may provide access tocomputing system 1400 with means of communicating and transferringsoftware and information electronically, and may be coupled directly tocomputing system 1400, or indirectly to computing system 1400, such asvia PSTN or cellular network 1480. Additionally, communications network1470 may provide for distributed processing, which involves severalcomputers and the sharing of workloads or cooperative efforts inperforming a task. It is appreciated that the network connections shownare exemplary and other means of establishing communications linksbetween multiple computing systems 1400 may be used.

It is appreciated that exemplary computing system 1400 is merelyillustrative of a computing environment in which the herein describedsystems and methods may operate, and thus does not limit theimplementation of the herein described systems and methods in computingenvironments having differing components and configurations. That is,the concepts described herein may be implemented in various computingenvironments using various components and configurations.

Further, the descriptions of the disclosure are provided to enable anyperson skilled in the art to make or use the disclosed embodiments.Various modifications to the disclosure will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other variations without departing from the spirit orscope of the disclosure. Thus, the disclosure is not intended to belimited to the examples and designs described herein, but rather is tobe accorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An end effector, comprising: a wafer support; a bearing arm capable of interfacing with at least one robotic element, and at least partially bearing the wafer support at one end thereof; a plurality of proximal and distal support pads on the wafer support for physically interfacing with a semiconductor wafer, wherein at least the distal support pads are ridged with a heightened back feature and an angled proximal feature to provide a wafer-edge stop; and a low friction moving clamp comprising two canted rollers driven bi-directionally along a plane at least partially provided by the bearing arm and a pivoting angular strike face capable of pivoting about a pivot joint, wherein the low friction moving clamp retractably forces the angular strike face against a proximal edge of the semiconductor wafer to cause the physical interfacing of the semiconductor wafer with the wafer-edge stop.
 2. The end effector of claim 1, wherein the heightened back feature of the ridge is also angled.
 3. The end effector of claim 1, wherein the wafer support comprises a fork.
 4. The end effector of claim 1, wherein the low friction clamp enables accommodation of varying sizes of wafers comprising at least 200 mm and 300 mm.
 5. The end effector of claim 1, wherein the bi-directional drive comprises at least a moving clamp motor.
 6. The end effector of claim 5, further comprising a low friction vacuum cylinder engaged for the moving clamp motor.
 7. The end effector of claim 6, wherein the vacuum cylinder provides low clamping forces from the low friction moving clamp.
 8. The end effector of claim 5, further comprising at least one retract stop that stops retraction of the low friction moving clamp after actuation of the low friction moving clamp by the bi-directional drive.
 9. The end effector of claim 8, wherein the at least one retract stop comprises a button.
 10. The end effector of claim 1, further comprising at least one travel stop that stops travel of the low friction moving clamp upon actuation by the bi-directional drive.
 11. The end effector of claim 1, wherein the low friction moving clamp comprises a rectangular strike face to apply the forces against.
 12. The end effector of claim 1, wherein the wafer support further comprises at least one vacuum eyelet for gripping the semiconductor wafer.
 13. The end effector of claim 1, wherein the wafer support further comprises a fiber optic wafer presence sensor. 